I think, keyattributes don't matter at all...

If so... my team shouldn't play the weakest season... I'm at 110 pts (=100%), my defender have ~130-140 pts, attacking player have more than 135 pts at attacking and physicals (~250% speed). Attacking of Costa is on incredible 163 points, 343% speed...
yes, he is my best scorer and best assister, but at the moment, it's going to be his worst season... far worse, than his beginning with ~80% gray skills.

And if I take a look at my opponents, there are a lot of oppo-player, their gray attributes are 80-110% - so in this case, my team should beat all opponents with around 5-16:0...
But I had a lot of trolls this season (luckily no lost game, but only 1:0 against 40% weaker, 3:2 agaist 32% weaker,...)